Occurrence of the tdh and trh genes in Vibrio parahaemolyticus isolates from waters and raw shellfish colleted in two France coastal areas and from seafood imported into France

Unité du Choléra et des Vibrions, Centre National de Référence des Vibrions et du Choléra, Institut Pasteur, 25, rue du Dr Roux, 75 724 Paris 15, France.
International Journal of Food Microbiology (Impact Factor: 3.08). 04/2004; 91(3):319-25. DOI: 10.1016/j.ijfoodmicro.2003.07.006
Source: PubMed


The occurrence of the hemolysin genes, tdh and trh, in Vibrio parahaemolyticus strains isolated from environmental samples collected in two French coastal areas, clinical samples, and seafood products imported into France was studied. Polymerase chain reaction (PCR) with two sets of primers was used to detect the hemolysin genes. Most of the clinical isolates (91%) and 1.5% of the isolates from seafood possessed the hemolysin genes. Three and fifteen percent, respectively, of the two groups of environmental strains carried the hemolysin genes depending on the geographic site. The tdh and trh genes play important roles in virulence. Thus, our results indicate that pathogenic V. parahaemolyticus isolates are present in French coastal areas and in seafood imported into France. Furthermore, they may also be present in French seafood products.

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Available from: Marie-Laure Quilici
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    • "When we considered the presence of pathogenic V. parahaemolyticus , tdh was not detected in any of the 483 toxR-positive (toxR+) samples, which is in agreement with the other field studies conducted in France (Hervio-Heath et al., 2002; Robert-Pillot et al., 2004). trh1 was detected in toxR+ samples of mussels and sediment but never of water. "

    Full-text · Dataset · Jun 2015
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    • "The virulence factors include thermostable direct hemolysin (TDH), TDH-related hemolysin (TRH), and type III secretion system (T3SS) (Kaper et al. 1984; Nishibuchi et al. 1986; Park et al. 2004). Most clinical isolates of V. parahaemolyticus exhibit Kanagawa phenomenon (KP) induced by TDH on Wagatsuma agar medium; however, only 1–3 % of the environmental isolates are KP positive (Shirai et al. 1990; Lozano-León et al. 2003; Robert-Pillot et al. 2004). TDH causes several cytotoxic effects, such as erythrocyte lysis, disruption of the microtubule cytoskeleton, and ion influx into cultured cells (Honda et al. 1988; Raimondi et al. 2000). "
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    ABSTRACT: Analysis of the genome sequence of Vibrio parahaemolyticus reveals two IcmF family genes in putative type VI secretion system (vpT6SS) clusters in chromosomes 1 (icmF1) and 2 (icmF2). The icmF1 gene is present in majority of clinical isolates (87.5 %), but has a low fraction (25.0 %) in environmental isolates. However, icmF2 is contained in all strains of both clinical and environmental sources. Deletion of either icmF1 or hcp1 significantly reduced bacterial adhesion to Caco-2 cells or HeLa monolayers. However, the ΔicmF2 and Δhcp2 mutants showed decreased adhesion only to HeLa monolayers. Western blot analysis showed that Hcp2 was present both in the supernatant and pellet samples in the wild-type strain, but only in the pellet of the ΔicmF2 mutant, indicating that Hcp2 is a translocon of T6SS2. Although vpT6SS1 might be functional in cellular adhesion, the putative translocon Hcp1 was not detectable. Quantitative PCR revealed 10-fold and 17-fold less transcripts of hcp1 and icmF1 mRNA than those of hcp2 and icmF2 accordingly. Thus, we postulate that the putative vpT6SS systems contribute to adhesion of V. parahaemolyticus to host cells.
    Full-text · Article · Apr 2012 · Archives of Microbiology
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    • "No trh+ strains were found in the rias located in the south of Galicia in a previous 3-year survey (Martinez-Urtaza et al., 2008b). The dominance of trh+ strains in the north of Galicia is consistent with previous observations in Northern Europe, where reduced numbers of trh+ strains were recovered in studies carried out in the English Channel and along the Atlantic coast of France (Hervio-Heath et al., 2002; Robert-Pillot et al., 2003), and in Norway (Bauer et al., 2006; Ellingsen et al., 2008). By comparison, no trh+ strains were recovered from the Mediterranean Sea, where only tdh+ strains were identified in environmental sources (Baffone et al., 2008; Caburlotto et al., 2008). "
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    ABSTRACT: The natural reservoirs and biological characteristics of pathogenic populations of Vibrio parahaemolyticus in marine habitats remain unclear due to difficulties in obtaining pathogenic strains from the environment. The distribution and characteristics of pathogenic V. parahaemolyticus were investigated over 1 year in three coastal environments in Galicia (Spain), including areas of the major international ports in the region. Vibrio parahaemolyticus was present in 35.3% of the samples analysed, and 535 strains were isolated over the period of study. Virulence genes were detected in 94 strains with diverse genetic traits: 66 trh+/tdh-, 24 trh-/tdh+ and 4 trh+/tdh+. Different spatial and seasonal patterns were observed in relation to genetic traits. The trh+/tdh- strains were detected exclusively in northern areas and prevailed in the autumn, when seawater is warmer and less saline, whereas the trh-/tdh+ strains were found in all three areas throughout winter and spring. Characterization of potentially pathogenic strains from the environment revealed an unexpectedly diverse array of serotypes and pulsed-field gel electrophoresis (PFGE) profiles (pulsotypes) that were unrelated to clinical strains of V. parahaemolyticus that are prevalent in Spain. The results of the current study provide a novel view of V. parahaemolyticus in Europe, in which diverse pathogenic groups are constitutive components of the environmental populations in coastal habitats.
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